Papers by Keyword: Explosive Welding

Abstract: The composites based on reactive metals (Zr, Ta, Nb, Ti) sheets explosively welded to stainless steel plates were investigated using X-ray synchrotron radiation, TEM and SEM to characterize phase transformations in near-the-interface layers. SEM and TEM investigations of the solidified melt regions unveiled amorphous and nanocrystalline non-equilibrium phases of variable chemical compositions, incorporating elements from the joined components. Phase analysis in layers near the interface carried out using high-resolution synchrotron radiation show predominantly reflections coming from the main elements of parent sheets/plates. Nevertheless, a closer look at the diffraction patterns shows the presence of reflections coming from the phases based on the two-component equilibrium phase diagrams. The measurements performed at the interface, but including only the steel plate, revealed significant amounts of α-Fe, γ-Fe and ε-Fe phases. Their appearance was attributed to the high pressure and fast cooling rates, which promoted a martensitic transformation in steel.

Abstract: In this work, the features of plastic deformation of titanium and aluminum plates under high-speed impact conditions were studied. The structure and phase composition of the explosively welded bimetal were analyzed using both scanning and transmission electron microscopy. The deformation and heating of titanium and aluminum under high-velocity impact were simulated using the smoothed particle hydrodynamics method. The features of shockwave and deformation-thermal processes during the collision of plates were described. The phase composition of the weld and heat-affected zone have been studied. The contribution of the welded plates to the jet formation is estimated.

Abstract: The interplay of various hardening and softening processes during explosive welding and post-processing annealing have been analysed in titanium/copper bimetallic sheets using scanning electron microscopy and microhardness measurements. Severe plastic deformation and intermetallics’ formation are typical processes leading to hardening, whereas dynamic/static recrystallization and the transformation of amorphous phases into crystalline ones lead to softening. In the as-welded state the interfacial layers of both parent sheets are severely deformed. However, they can undergo intense recrystalization in areas near large melted zones. Inside the melted zones a wide variety of chemical compositions can be detected, however, most of the phases do not appear in the Ti-Cu equilibrium phase diagram. The post-processing annealing at 973 K for 1 h leads to full recrystallization of severely deformed layers of parent sheets and transforms the non-equilibrium phases forming melted zone into the equilibrium TiCu₄ and Ti₃Cu₄ ones via spinodal decomposition. Simultaneously, the growth of four intermetallic layers: Ti₂Cu, TiCu, Ti₃Cu₄, TiCu₄ situated along the whole interface was detected.

Abstract: The paper presents the results of research on the creation of heat-resistant composite A5-Cr-St3 with diffusion barrier. It considers the influence of the thickness of the chromium layer and the kinematic parameters of the structure and thermal steel-aluminum composite.

Abstract: This paper discusses the structure and regularities of formation of compounds during explosive welding plate steel-aluminum composite. The influence of thickness of the welded element on the structure and the shear deformation of the metal in the heat-affected zone under different conditions of explosive loading was investigated.

Abstract: The aim of this work was to investigate whether the low alloy steel and the explosively welded metals used for salt caverns equipment's are susceptible to hydrogen degradation. The materials described in this article are cheap and widely used 09G2S low alloy steel and titanium grade1 as a clad material for its superior resistance to corrosive environment joined explosively with low alloy steel S355J2+N. It was observed that at the explosive bonded interface between the base steel and the stainless steel some local melting zones are formed. It was found that the cathodic hydrogen charging causes changes in the microstructure of low alloy steel and decreases the shear strength of bonds and tensile stress as well as the corrosion resistance of clads.

Abstract: The aim of this work was to investigate whether the explosively welded metals are susceptible to hydrogen degradation. The materials described in this article are widely used nickel alloy Inconel C-276 and super duplex steel SAF 2507 as clad materials for their superior resistance to corrosive environment and low alloy steel P355NH as a base material. It was observed that at the explosive bonded interface between the base steel and the stainless steel some local melting zones are formed. It was found that the cathodic hydrogen charging causes changes in the microstructure of bonded materials and decreases the shear strength of bonds as well as the corrosion resistance of clads.

Abstract: In this investigation, thin Aluminum alloys 2A12 and Copper T2 composite plates which are both 1mm thick were obtained successfully by the method of explosive welding. The effect of annealing on the interface microstructures of the composite plates was investigated under different temperatures. Optical microscopy, scanning electron microscopy, micro-hardness test and bending test were performed. The results demonstrated that the Al/Cu composite plates were bonded well. The bonding interface of the Al/Cu composite plates had a wavy form. Micro-hardness measurements showed that the hardness of the composite plates near the interface was higher than other parts and the hardness of the whole composite plates was lower after annealing. The bending test showed the composite plates can be deformed or shaped.

Abstract: In order to study the explosive welding experimental fabrication technology of multi-layer dissimilar metal plates and the quality of bonding interface, three-layer steel/aluminum/steel composite plates with different thickness distributions were fabricated using the method of explosive welding when their total thicknesses remained same (total 5 mm). Then the stereomicroscope was adopted to investigate the shape of bonding interface and the formed mechanism was also analyzed. In addition, the micro-hardness (Vickers hardness, Hv) distribution of the composite plate in the thickness direction was studied by a low load Vickers hardness tester. The results show that the method of explosive welding can be used to fabricate three-layer steel/aluminum/steel dissimilar metal plates successfully. Meanwhile, wave bonding interface was formed between steel fly plate and aluminum middle plate, straight bonding interface was formed between aluminum middle plate and steel base plate. The maximum Hv value of welded plate appears at the bonding interface with high bonding strength. The bonding strength of both two kinds of welded interface was considered sufficient, which offers experimental support for the explosive welding of multi-layer plates.

Abstract: This paper presents the results of the effect of ultrasound on explosion welded materials. It was found that simultaneous treatment with ultrasonic vibrations and explosion welding of the materials to be welded has a significant effect on the structure and properties of the heat-affected zone of formed aluminum and copper joints. It has been experimentally proved that the change in the sizes and structure of the weld junction during explosion welding using high-frequency vibrations is a result of the simultaneous action of these processes at the stage of joint formation and hardly depends on the structure of the material.